Paper drying apparatus



1955 A. P. SCHNYDER 3,

PAPER DRYING APPARATUS Filed April 14, 1964 2 Sheets-Sheet 1 FIG. 1

INVENTOR. AUX IL\ US P. SCHNYDER BY MMIQWA W 75 104 6 Eda/n4.-

ATTORNEYS Nov. 8, 1966 A. P. SCHNYDER 3,283,415

PAPER DRYING APPARATUS Filed April 14, 1964 2 Sheets-sheet 2 my, I InINVENTOR. AUXILIUS P. SCHNYDER BY mmg 771 1 4 W dda/VKL ATTOR N EYSUnited States Patent 0 3,283,415 PAPER DRYING APPARATUS Auxilius P.Schnyder, 146 Cherry Lane, Teaneck, NJ. Filed Apr. 14, 1964, Ser. No.359,682 2 Claims. (Cl. 34-111) This application is acontinuation-in-part of my prior application Serial No. 262,544, filedMarch 4, 1963, now abandoned.

This invention relates to paper drying apparatus of the type havingdrying cylinders provided with dryer felt for absorbing moisture fromthe paper, and provides an improved means to vaporize the moisture inthe felt and in the paper, and to remove the moisture from the area ofvaporization.

It is customary to dry paper by passing it continuously and at a uniformrate over a multiplicity of heated drying cylinders consisting of uppercylinders mounted in a horizontal plane and lower cylinders also mountedin a horizontal plane. The drying apparatus may be described asincluding a succession of three cylinder units the axes of which form atriangle, one unit having two cylinders below and one cylinder above andthe adjacent unit having one cylinder below and two cylinders above.

The web of paper undergoing drying is passed continuously from oneheated cylinder to another and two endless dryer felts are employed inthe apparatus, one travels over the paper while it is in contact witheach upper cylinder and the other passes over the paper while it is incontact with each lower cylinder. Between each adjacent pair of lowercylinders and each adjacent pair of upper cylinders, a roller is mountedto direct the dryer felt over a substantial area of the paper which isin contact with the cylinders. The paper passes over a lower cylinder,upward over the upper cylinder and downward over the other lowercylinder. An endless web or belt of porous dryer felt which is incontact with the paper on each cylinder absorbs moisture from the paper.It is customary to return the endless webs of dryer felt along directionand tension rollers. Means are usually employed to heat this returningsection of the felt web to evaporate the moisture. Duct means have beensuggested heretofore for removing moisture vapor from the area of thedrying rollers. Perforate felt drying rollers have also been suggestedfor use between the drying rollers over which the dryer felt passestogether with means to suck moisture out of the felt.

This invention provides a duct system for forcing air, preferably dryhot air, into and across new open grillage drying rollers and throughthe pores or fibers of the overlying dryer felt, and also an exhaustduct system for removing moisture laden air from the felt. The exhaustduct system is preferably constructed and arranged to remove water vaporfrom an area between the drying cylinders which is evaporated from thesurface of the paper, particularly from the free runs of paper passingfrom one cylinder to the next, and also includes selective provisionswhich prevent paper being accidentally sucked into the duct system.

The apparatus of the invention comprises a manifold extending along eachopen grillage roller for forcing hot air into and across the opengrillage roller and through the felt overlying the open grillage roller,and an exhaust duct means located along and over the outside of eachopen grillage roller so as to receive the moisture laden air forcedthrough the felt and sweeping the surface of the paper, and carry itunder reduced pressure to an outside vent. There is an appreciableamount of water evaporated directly from the paper and the exhaust ductsystem is constructed and arranged to remove this additional Ice watervapor from the area between the two adjacent runs of paper passing fromone cylinder to the next cylinder.

Preferably, the apparatus comprises a cap or hood extending lengthwiseof each open grillage roller for forcing vhot unsaturated drying airthrough the dryer felt transversely either uniformly or at differentcontrolled rates over the segmental portions making up the entire widthof the felt web, and a vapor collecting duct means extending the fullwidth of the open grillage rollers and drying cylinders connected to anexhaust air system operated under reduced pressure which removes themoisture laden air transversely over the entire width of the web ofpaper. The means of adjusting the rate of air sectionally across thewidth of the system will make it possible to compensate for any lack ofuniformity of absorbing the moisture laden air into the exhaust duct.

The apparatus of the invention effects a more rapid and efficient dryingof the paper with a reduced volume of drying air, uniform drying overthe width of the paper web, and better control. The drying apparatus canbe adjusted to obtain a uniform moisture profile at the exit end, andthe protection of the paper from entrained lint and surface dirt.

Each exhaust duct is shaped to divide the air in accordance with therelative needs as the air enters through the felt into the vapor spaceformed by the free spaces of paper between upper and lower dryingcylinders, and between the one paper drying cylinder and the feltcovered open grillage roller, one above the other, with the exhaust ductbeing placed in this vapor space. The major portion of the air isdirected toward the oncoming web of paper with its hotter side havingbroken contact with the heated drying cylinder being exposed so that theair will sweep this side clear of the film of water vapor before beingsucked into the exhaust duct. The lesser portion of air is directed tosweep the colder side of the Web of paper leaving the processing dryer,and is then sucked into the exhaust duct through open slots on theopposite side of the duct. Both slots extend the full width of the duct.The slots have an open mesh wire covering to prevent occasional shredsof paper from being sucked into the duct and clog the entire exhaustduct system.

The exhaust duct being rigidly framed for spacing the full width of themachine without deflecting serves to support the doctor blade withbuilt-in adjustments for contacting the drying cylinder or backing off.

These and other novel features of the invention will be betterunderstood after considering the following discussion and accompanyingdrawings in which FIG. 1 is a vertical end view of one unit of paperdrying apparatus embodying the invention;

FIG. 2 is a sectional view of a modification of the apparatus of FIG. 1;

FIG. 3 is a longitudinal side view of a felt drying apparatus of theinvention;

FIG. 4 is an enlarged view, partly in section, of the left end portionof FIG. 3, and FIFIG. 5 is an enlarged sectional view taken at 55 of Itis understood that a complete paper drying apparatus comprises severalupper drying cylinders 1 arranged in a horizontal plane and severallower drying cylinders 2 also arranged in a horizontal plane, and thatthere is a continuous upper drying felt 3 which passes over the paper onthe upper cylinders and a continuous lower drying felt 4 which passesover the paper on the lower cylinders. The felt is made of a porousmoisture absorbing material and means are provided to maintain propertension on the drying felts, all well known in the art. For conveniencein describing and claiming the invention, the upper cylinder and the twolower cylinders have been 1 called a unit.

, drying apparatus.

There are repeating similar units comprising the complete apparatus.

The web of paper 5 passes continuously over the cylinders which areusually heated, as indicated by the arrows and the upper drying felt 3passes with the paper on the upper cylinder absorbing moisture from thepaper and the lower drying felt 4 passes with the paper on the lowercylinders 2 absorbing moisture from the opposite side of the paper. Theopen grillage rollers 6 and 7 for the upper cylinders and the opengrillage rollers 8 for the lower cylinders are located as is usual inthis art so as to provide a large peripheral area of contact of thedrying felts with the paper on the cylinders. As best shown in FIGS. 3,4 and 5, each open grillage roller has end shafts 10 and 11 mounted inbearings Hand 13 which are attached to side portions 14 and 15 of theThe shafts are secured to hubs 16 and 17 to which a plurality of spacerribs 18 are secured. These ribs have relatively wide bearing surfaces 19and shanks 20 by means of which they are secured to spacer support rings22. The entire open grillage roller is machined to a high degree ofuniformity and the exterior surfaces 19 are smooth to prevent injury tothe felt.

The means for forcing dry hot air into the open grillage roller andthrough the felt comprises a hood 23 supported below the open grillageroller 8 as shown in FIGS. 1 and 2. The hot air is supplied to the hoodthrough the duct 24. The hood has end closures 25 and 26 which bearagainst rings 27 and 28 on the hubs to prevent a loss of airtransversely. As best shown in FIGS. 2 and 5,

the longitudinal edges 31 and 32 of the hood are bent for fittingconcentrically with the open grillage roller, with a safe minimumclearance between the hood and .the roller, and with a sufficient gapbetween the edges of the hood and the drying felt to prevent wear andtear of either, as is probable with actual contact between the two. Theescapement of hot drying air through the gap between felt and hood isminimized by the bent edge .of the hood which deflects the air towardthe felt, so

that substantially all of the air is forced into and through the porousfelt. The moisture exhaust conduit 35 of the invention is mounted overand extends the length of the open grillage rollers and is supported atits ends by brackets 36 and 37 attached to the machine support frames 14and 15. The brackets are connected to duct 38 which leads to a lowpressure system operated by an exhaust fan (not shown). The exhaustconduit comprises a duct 40 having wide slots 41 and 42 which may haveperforations or be covered with wire mesh 43 and 44 extending theentirelength of the duct. These screened or perforated openings arelocated so as to remove the moisture laden air from the dryerfelt andalso the moisture evapcrating from the free runs of the paper passingfrom one cylinder to another. The exhaust conduit not only carries awaythe moisture laden air from the drying felt and the free runs of thepaper but it tends to reduce the pressure in the surrounding area whichincreases the evaporation rate.

The duct 35 is preferably shaped as shown in crosssection to form adepending baffle or deflector nose 46 'which directs the major part ofthe air towards the left sibility of shreds of paper during start-up andoccasional breaks being sucked into the duct with the possibility thatsuch shreds of paper might clog the duct or the following systementirely.

The apparatus illustrated in FIG. 2 provides a pivotal support fordoctor blade 47, which can be made to contact the surface of the uppercylinder 1, or can be retracted to leave a gap between the blade and thecylinder. The doctor blade 47 removes. lint and pulp fibers from thecylinder which are carried away by theexhaust conduit or scrapes offpaper while it is threaded into the machine. or sticks to the surface ofthe cylinder due to a snap off, the paper being transferred into thefollowing nip between the drying cylinder and felt.

I claim: a

1. In paper drying apparatus having a multiplicity of cylinder unitsconsisting of one upper cylinder, two lower cylinders in a triangularspaced relation with the upper cylinder and with means for passing paperover the cylinders and drying felt over the paper on the cylinders, twoopen grillage felt drying rollers one on each side of the upper cylinderand an open grillage felt drying roller between the two lower cylinders,the improvement which comprises a hood extending lengthwise of each opengrillage roller provided with means to force hot air through the opengrillage roller and the overlying felt, an exhaust conduit supported inthe space between the two lower cylinders and the upper cylinder andextending lengthwise thereof, said conduit having an opening extendinglengthwise for the transverse entry of moisture laden air from thedrying feltand moisture laden air from between the adjacent runs ofpaper web passing adjacent the exhaust conduit, said openingsbeing of asize to prevent shreds of paper being sucked into the conduit,

a removable doctor blade bearing on the upper cylinder for scraping offlint and fibers: which are removed by the exhaust conduit, and means tooperate the exhaust conduit under reduced pressure.

2. In paper drying apparatus having amultiplicity of cylinder unitsconsisting of one upper cylinder, twolower cylinders in atriangularspaced relation with the upper cylinder and with means for passing paperover. the cylinders and drying felt over the paper on the cylinders, twoopen grillage feltdrying rollers one .on each side .of the upper.cylinder. and an open grillage felt drying roller between the two lowercylinders, the improvement which comprises a hood extending lengthwiseof each open grillage roller provided with means to force hot airthrough the open grillage roller and the overlying felt, an exhaustconduit extending lengthwise of each open grillage roller for removingvapor laden air over the width of the open grillage roller, said conduithaving a .per-

forated surface which permits entry of lint and fibers but erate theexhaust conduit under reduced pressure.

References Cited by the Examiner FOREIGN PATENTS 3/1937 Great Britain.3/1941 Great Britain.

JAMES w. WESTHAVER, Primary Examiner.

1. IN PAPER DRYING APPARTUS HAVING A MULTIPLICITY OF CYLINDER UNITSCONSISTING OF ONE UPPER CYLINDER, TWO LOWER CYLINDERS IN A TRIANGULARSPACED RELATION WITH THE UPPER CYLINDER AND WITH MEANS FOR PASSING PAPEROVER THE CYLINDERS AND DRYING FELT OVER THE PAPER ON THE CYLINDERS, TWOOPEN GRILLAGE FELT DRYING ROLLERS ONE ON EACH SIDE OF THE UPPER CYLINDERAND AN OPEN GRILLAGE FELT DRYING ROLLER BETWEEN THE TWO LOWER CYLINDERS,THE IMPROVEMENT WHICH COMPRISES A HOOD EXTENDING LENGTHWISE OF EACH OPENGRILLAGE ROLLER PROVIDED WITH MEANS TO FORCE HOT AIR THROUGH THE OPENGRILLAGE ROLLER AND THE OVERLYING FELT, AN EXHAUST CONDUIT SUPPORTED INTHE SPACE BETWEEN THE TWO LOWER CYLINDERS AND THE UPPER CYLINDER ANDEXTENDING LENGTHWISE THEREOF, SAID CONDUIT HAVING AN OPENING EXTENDINGLENGTHWIDE FOR TRANSVERSE ENTRY OF MOISTURE LADEN AIR FROM THE DRYINGFELT AND MOISTURE LADEN AIR FROM BETWEEN THE ADJACENT RUNS OF PAPER WEBPASSING ADJACENT THE EXHAUST CONDUIT, SAID OPENINGS BEING OF A SIZE TOPREVENT SHREDS OF PAPER BEING SUCKED INTO THE CONDUIT, A REMOVABLEDOCTOR BLADE BEARING ON THE UPPER CYLINDER FOR SCRAPING OFF LINT ANDFIBERS WHICH ARE REMOVED BY THE EXHAUST CONDUIT, AND MEANS TO OPERATETHE EXHAUST CONDUIT UNDER REDUCED PRESSURE.